VOLUME 1: Executive Summary · 2019-12-04 · Project No PS102571 RAAF Base Townsville - Ecological Risk Assessment (ERA) Volume 1: Main Report Department of Defence WSP December

DEPARTMENT OF DEFENCE

RAAF BASE TOWNSVILLE - ECOLOGICAL RISK ASSESSMENT (ERA) VOLUME 1: Executive Summary

DECEMBER 2019

PUBLIC

Project No PS102571 RAAF Base Townsville - Ecological Risk Assessment (ERA) Volume 1: Main Report Department of Defence

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ACRONYMS 6:2 FtS 6:2 Fluorotelomer sulfonate

AFFF Aqueous Film Forming Foam

ANZECC Australian and New Zealand Environment Conservation Council

ARMCANZ Agriculture and Resource Management Council of Australia and New Zealand

ATSDR Agency for Toxic Substances and Disease Registry

AVN Aviation

BAF Bioaccumulation Factor

BW Body Weight

COPC Chemicals of Potential Concern

CRC CARE Cooperative Research Centre for Contamination Assessment and Remediation of the Environment

CSM Conceptual Site Model

CSR Contaminated Sites Register

DEHP Department of Environment and Heritage Protection

DES Department of Environment and Science

DILGP Department of Infrastructure, Local Government and Planning

DIWA Directory of Important Wetlands

DNRM Department of Natural Resources and Mines

DoEE Department of Environment and Energy

DoH Department of Health

DSI Detailed Site Investigation

DSITI Department of Science, Information, Technology and Innovation

DW Dry Weight

EILs Ecological Investigation Levels

EC Environment Canada

EPBC Environment Protection and Biodiversity Conservation

EPC Exposure Point Concentration

EPP Environmental Protection (Water) Policy

ERA Ecological Risk Assessment

ESP Ecological Service Professionals Pty Ltd


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FEQG Federal Environmental Quality Guidelines

FHA Fish Habitat Area

FSANZ Food Standards Australia New Zealand

GBRMP Great Barrier Reef Marine Park

GSE Ground Support Equipment

HBW Handbook of the Birds of the World

HEPA Heads of EPAs Australia and New Zealand

HHRA Human Health Risk Assessment

HI Hazard Index

HQ Hazard Quotient

HR Home Range

IA Investigation Area

IUCN International Union for Conservation of Nature

LC Lethal Concentration

LD Lethal Dose

LOAEL Lowest Observed Adverse Effect Level

LOR Limit of Reporting

mAHD Metres Australian Height Datum

mBGL Metres Below Ground Level

mg/kg Milligrams per kilogram

MNES Matters of National Environmental Significance

MSES Matters of State Environmental Significance

NA Not Applicable

NEMP National Environmental Management Plan

NEPC National Environment Protection Council

NEPM National Environment Protection Measure

NOAEL No Observed Adverse Effect Level

NPRSR Department of National Parks, Recreation, Sport and Racing

OECD Organisation for Economic Cooperation and Development

OLA Ordnance Loading Apron

PFAS Per- and polyfluoroalkyl substances

PFBS Perfluorobutane sulfonic acid


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PFDA Perfluorodecanoic acid

PFDS Perfluorodecane sulfonic acid

PFHxA Perfluorohexanoic acid

PFHxS Perfluorohexane sulfonic acid

PFNA Perfluorononanoic acid

PFOA Perfluorooctanoic Acid

PFOS Perfluorooctane Sulfonate (alternative name Perfluorooctane sulfonic acid)

PFPeA Perfluoropentanoic acid

PFPeS Perfluoropentane sulfonic acid

PMST Protected Matters Search Tool

RAAF Royal Australian Air Force

ROC Receptor of Concern

SAQP Sampling Analysis and Quality Plan

SPP State Planning Policy

SQN Squadron

SSD Species Sensitivity Distribution

SWL Standing Water Level

TA Technical Advisor

TBA To Be Advised

TCC Townsville City Council

TDS Total Dissolved Solids

TRV Toxicity Reference Value

UCL Upper Confidence Limit

UF Uncertainty Factor

US EPA United States Environmental Protection Agency

WTP Water Treatment Plant

WW Wet Weight


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GLOSSARY OF TERMS TERM DEFINITION

Amphibian A class of animals that live both on land and in water, comprising cold-blooded vertebrates including frogs, toads and salamanders.

Aquatic Relating to water.

Aquifer A geological formation capable of conducting and transmitting water.

Arboreal Animals which live or spend majority of their time in trees.

Avian Relating to birds.

Background sample A sample collected from a location deemed to be representative of natural conditions, exclusive of potential anthropogenic (man-made) contamination sources or activities.

Benthic Relating to or occurring at the lowest level of a body of water; it includes the sediment surface.

Bioaccumulation The accumulation of substances in an organism at a rate faster than it can be excreted by that organism.

Biodegradation The process by which organic substances are decomposed by micro-organisms into simpler substances such as water, carbon dioxide and ammonia.

Biomagnification The increase in concentration of a substance within a food chain as it moves from one trophic level to the next.

Biota The animal and plant life of a particular region.

Catchment The area from which a surface watercourse or a groundwater system derives its water.

Direct toxicity The hazardous potential of a substance based on its interaction with an organism by directly altering metabolic processes or molecular structures.

Ecological receptor An animal, plant, or ecosystem that may be detrimentally affected by exposure to PFAS.

Exposure pathway The pathway a contaminant takes from its source via a medium (air, soil, surface water, groundwater) to a receptor which represents a potential hazard to that receptor.

Exposure point concentration

A conservative estimate of the concentration of a substance (PFAS in the context of this ERA) available in the environment (e.g., soil, sediment and water) to which receptors can be exposed.

Food chain A linear sequence of organisms through which energy and nutrients pass as one organism eats another.

Food web A natural inter-connection of food chains in an ecological community, depicting organisms related by predator-prey and consumer-resource interactions.

Herbivorous Feeding on plants.

Higher order species A taxonomic rank used to classify organisms, considered to be complex organisms, for example mammals, birds.


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TERM DEFINITION

Invertebrate An animal without a backbone or spinal column, such as insects.

Invertivorous Feeding on invertebrates.

Investigation Area RAAF Base Townsville and surrounding areas defined on Figure 1, Appendix A.

LOAEL Lowest observed adverse effect level – the lowest level at which there was an observed adverse effect in people or animals.

Lower order species A taxonomic rank used to classify organisms, considered to be simple organisms, for example plants, invertebrates.

Media/medium The substance in which an organism lives.

NOAEL No observed adverse effect level – the highest level at which there was not an observed adverse effect in people or animals.

Omnivorous Feeding on food of both plant and animal origin.

Point of exposure The place where an organism can come into contact with a substance in the environment.

Precursor A substance that participates in a chemical reaction from which PFOS and PFOA may be formed.

Risk assessment A systematic process of evaluating the potential risk that may be posed by a hazardous substance (PFAS in the context of this ERA) to a receptor in a system.

Soluble Susceptible to being dissolved in a liquid, especially water.

Source A potentially hazardous substance that may be released to the environment (PFAS in the context of this ERA).

Terrestrial Living or growing on land rather than in water or air.

Trophic level A group of organisms within an ecosystem that occupy the same level of a food chain, e.g. producers, primary consumers, secondary consumers, predators.

TRV Toxicity reference value is the exposure concentration or dose of a contaminant (PFAS in the context of this ERA) that is not expected to cause an unacceptable level of effect in a receptor of concern.

UF Uncertainty Factor – a conservative tool to deal with uncertainty in establishing exposure limits.

Typically, UFs are applied for the following three elements:

— laboratory to field extrapolation — acute to chronic toxicity extrapolation; and — interspecies extrapolation.

Vertebrate An animal that has a backbone or spinal column, including mammals, reptiles, birds, amphibians, fish.

Volatility Tendency of a substance to evaporate at normal temperatures.


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EXECUTIVE SUMMARY

BACKGROUND WSP Australia Pty Ltd (WSP) was commissioned by the Department of Defence (Defence) under the Defence per- and poly-fluoroalkyl substances (PFAS) Panel to conduct an Ecological Risk Assessment (ERA). The ERA was undertaken to quantitatively assess the risk to ecological health resulting from potential environmental exposure to PFAS, contained in legacy Aqueous Film Forming Foams (AFFF), used at the Royal Australian Air Force (RAAF) Base Townsville (herein referred to as ‘the Base’). The Base is located on Ingham Road, Garbutt, Queensland 4180.

AFFF were stored and used by Defence at the Base for fire-fighting purposes, including routine testing and emergency fire-fighting response practice drills, from approximately the 1970s to 2004. AFFF containing PFOS and PFOA as active ingredients was phased out in approximately 2004 and replaced by another product (Ansulite).

WSP completed a Detailed Site Investigation (DSI) (WSP 2018a) of the Base and surrounding off-Base areas, including the Townsville Town Common Conservation Park (the Town Common) and the suburbs of Garbutt, Rose Bay, Belgian Gardens and Pallarenda (the ‘Investigation Area’) between April 2017 and February 2018. This report was publicly released in May 2018 by the Department of Defence and presented at a Community-Walk-In-Session.

The ERA also incorporates environmental analytical results collected across the Investigation Area following the rainfall events that occurred across the catchments in post-March 2018. This dataset was presented in the Seasonal Monitoring Report 1 (WSP 2018b).

The ERA also includes aquatic and semi-terrestrial biota analytical results from investigations conducted across the Investigation Area and Cleveland Bay between July 2017 and March 2018. The complete dataset which comprises environmental, aquatic and semi-terrestrial biota results, including the supporting technical reports prepared by those engaged by WSP, to collect the samples ethically, are appended to this report.

The approach to assessing potential risks to the identified ecological receptors within the Investigation Area comprised of two steps:

1 Potential risks to lower order species (i.e. plants, terrestrial/aquatic invertebrates and fish) were assessed by comparing available data to a screening benchmark (criteria) (i.e. the evaluation of direct toxicity); and

2 Potential risks to identified higher order species (i.e. predatory birds, mammals and reptiles) within the Investigation area, were evaluated via quantitative food web modelling (i.e. the evaluation of indirect exposure risk).

This ERA has undergone a rigorous technical review process including:

— an independent Technical Advisor (TA) who is accredited by the Queensland Department of Environment and Science (DES) as a Contaminated Land Auditor (CLA); and

— the Technical Working Group established by the Queensland Government Interdepartmental Committee for Fluorinated Fire Fighting Foam which draws together expertise from the Queensland State Government including Queensland Health and DES.


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OBJECTIVES The purpose of the ERA was to consider potential risks to ecological receptors from direct exposure to PFAS in environmental media, as well as indirect exposure that may occur through dietary intakes of PFAS in various organisms, forming part of the food chain.

The objectives of the ERA are to:

— assess, quantitatively and qualitatively, potential ecological health risks to ecological receptors within the Investigation Area that may be inadvertently exposed (via direct contact), to PFAS impacted environmental media (i.e. soil, groundwater, surface water and sediment) from the Base; and

— assess quantitatively, the potential for risks to higher order species from the transfer of PFAS, from lower order, to higher order species within the terrestrial/semi-terrestrial and aquatic food webs.

FIELD INVESTIGATION FINDINGS Environmental samples (i.e. soil, groundwater, surface water and sediment), aquatic biota samples (i.e. fish, crustaceans, plants), as well as semi-terrestrial biota samples (i.e. reptiles and amphibians) collected in the field, underwent an initial screening process against published relevant criteria for each media investigated.

The purpose of the screening process was to determine if a sampled media returned results that were above the adopted screening criteria. If the concentrations were found to be above the screening criteria, for a particular media, then additional assessment via the ERA was required to assess the ecological risk.

A review of the on-Base soil data was undertaken across different areas including operational areas with a view, that any identified impacts in soil on-Base, may contribute to off-Base ecological impacts. The reported on-Base soil results indicated that PFOS concentrations in soil at several different areas on the Base were above the adopted ecological screening criteria for an industrial/commercial land use and warranted further evaluation in the ERA. Conversely, concentrations of PFOA in soil were not identified above the screening criteria for ecological risks. Hence, PFOA was not considered to warrant further evaluation.

A review of the off-Base soil data collected from surrounding suburbs from the Base including Bohle, Belgian Gardens, Cleveland Bay, Rowes Bay, the Town Common, Garbutt Community and Pallarenda did not identify concentrations of PFOA to be above the ecological screening criteria. The off-Base soil results obtained during the additional wet season sampling (WSP 2018b) (which targeted properties where PFAS-impacted groundwater was reported in the DSI (WSP 2018a)), did identify concentrations of PFOS in soil (from Rowes Bay, Garbutt and Pallarenda) exceeding ecological screening criteria for an industrial/commercial land use and/or residential land use.

PFAS has been detected in groundwater from most of the monitoring wells on the Base. However, the absence of PFAS in isolated monitoring wells suggests that there isn’t one continuous PFAS ‘plume’ beneath the Base, but a series of PFAS ‘plumes’ related to specific source areas and possibly surface water bodies. Plumes were interpreted to extend to the east and north-east from the south-eastern section of the Base, west and north-west from 5 AVN and north from the northern end of the runway. The highest PFAS concentrations were generally reported from monitoring wells installed at the known source areas; or immediately downgradient of the source areas.

The detection of PFAS in off-Base monitoring wells to the north-west, north, north-east, south-east and east of the Base suggested that groundwater ‘plumes’ have transported PFAS off-Base in these directions. The DSI concluded that the groundwater impacts are not continuous ‘plumes’ in the traditional hydrogeological sense but rather, are more likely to occur at distances from the Base, due to surface water PFAS transport, with subsequent infiltration of PFAS impacted water into the underlying aquifer. Evidence of this transport mechanism appears to be occurring in the surface water bodies of the Town Common, Three Mile Creek and Mundy Creek catchments.


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PFAS was detected in surface water and sediment on- and off-Base at concentrations above the ecological screening criteria (benchmarks). The results indicate that PFAS is being transported by surface waters from the Base into the Town Common, Louisa Creek, Three Mile Creek and Mundy Creek catchments. At the time of the DSI investigation, there was no surface water flow from the Base. However, a period of higher flow was observed in the dataset collected for the Seasonal Monitoring Report 1 with elevated PFAS concentrations observed discharging from the Base. It appears that PFAS impacted sediments found at a distance from the Base have been transported to those locations bound to the sediments in these high flow events. Results of samples collected up-gradient of the Base indicate a background source of PFAS exists in the upper catchments of Louisa and Peewee Creeks and in the middle reaches of the Bohle River. However, compared with the concentrations recorded in surface waters discharging from the Base, the background up-gradient input of PFAS concentrations to the Investigation Area is considered to be minor.

Four aquatic biota surveys were completed by Ecological Service Professionals Pty Ltd (ESP) with biota sampling and analysis completed in freshwater, estuarine and marine environments, targeting areas with known PFAS impacts within the Investigation Area, and comparative sites outside the Investigation Area. The complete off-Base aquatic biota dataset is provided in Appendix B of the ERA.

During the first survey in July 2017, concentrations of PFOS and PFHxS were highest in biota samples collected from the Bohle River and Town Common, estuarine systems, generally within fish species, particularly the detritivores (i.e. consume detritus and organic matter) and consumers (i.e. fish that eat other organisms including other fish). Comparative site locations that were sampled within 10 km of the mouth of the Bohle River indicated that the elevated concentrations (i.e. exceeding adopted screening criteria) detected within the Bohle River (located within the Investigation Area) do not extend to this extent (only two biota samples exceeded screening criteria).

Concentrations of PFOS and PFHxS were generally reported at higher concentrations within whole and liver samples compared to fish flesh, and in whole crustaceans compared with flesh alone. It was detected amongst all trophic levels in the Town Common and the majority of trophic levels in Bohle River. Concentrations increased in higher trophic levels. However, high concentrations were also observed in fish detritivores. The first survey did not include large predatory fish. However, the presence within species such as mullet (a food source for predatory species) indicates PFOS and PFHxS is available to larger predatory species. Subsequent surveys which did include large predatory species found that the majority of liver samples contained detectable PFOS + PFHxS concentrations and the marine survey generally found the highest concentrations within predatory species as discussed below.

The second survey conducted in November/December 2017 was undertaken within three estuarine impact sites within the Investigation Area and two comparative estuarine sites outside the Investigation Area. PFOS and PFHxS were again the most widespread PFAS compounds detected and within the impact sites these PFAS compounds were detected in 76% of fish or crustacean biota samples. PFAS was not detected within any plant samples. At the comparative sites, only 8% of all biota samples reported detectable concentrations of PFOS and/or PFHxS.

The third aquatic survey comprised analysis of marine biota samples collected from south-west of Magnetic Island, Rowes Bay, Althaus Creek and Bohle River in March 2018. Two sites (Bohle River mouth and Rowes Bay) were located within the Investigation Area and three sites represented comparative sites outside the Investigation Area (Magnetic Island and Althaus Creek).

PFOS and PFHxS were the most widespread PFAS compounds detected (detected in 46% of all samples, 53% of samples from impact sites, and 36% of samples from comparative sites); and Bohle River reported most of the elevated PFOS and PFHxS. Of the impact sites, the highest concentrations were detected in liver samples of apex predators (barred queenfish or barramundi) from the Bohle River mouth. A consumer species (blue catfish) from Rowes Bay also reported one of the highest concentrations.

From samples collected at the comparative sites, the highest concentration of PFOS and PFHxS was reported within a detritivore liver sample of a diamond scale mullet, collected from Althaus Creek mouth. Mature mullet are known to migrate long distances and so it is possible that exposure may be a result of time spent within other environments more akin to the impact sites located within the Investigation Area.


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A semi-terrestrial fauna survey and sampling program was undertaken in February 2018. A total of 84 semi-terrestrial fauna biota samples (comprising a mixture of reptiles and amphibians) were collected from four separate sampling locations, three within the Investigation Area and one comparative site, outside the Investigation Area. Concentrations of PFOS and PFHxS were detected in semi-terrestrial fauna species sampled at each of the four locations. Considering all semi-terrestrial fauna biota samples, 93% of those collected within the Investigation Area contained a PFOS and PFHxS concentration exceeding the adopted ecological screening criteria. The off-Base semi-terrestrial biota dataset is provided in Appendix B of the ERA.

Within amphibians, the cane toad consistently reported higher average concentrations of PFOS and PFHxS at each sampling location, and amphibians from the Town Common reported the highest average PFOS and PFHxS concentrations followed by the wetland in Rowes Bay, Louisa Creek Wetland and Alligator Creek. The combined average of PFOS and PFHxS concentration reported in amphibians from the Investigation Area was 67 µg/kg and therefore exceeded the adopted ecological screening criteria.

Within reptiles, the freshwater snake reported higher average concentrations of PFOS and PFHxS compared to the Canns Longnecked turtle, and the highest concentrations in biota samples by far were reported in the Town Common, followed by the wetland in Rowes Bay and Louisa Creek Wetland. Concentrations of PFOS and PFHxS in samples of freshwater snake from the Town Common were generally an order of magnitude higher than the Canns Longnecked turtle. Samples from the comparative site Alligator Creek did not contain detectable concentrations of PFOS and PFHxS (based on four freshwater snake samples). The combined average PFOS and PFHxS concentration reported in reptiles from the Investigation Area was 1,152 µg/kg and therefore exceeded the adopted ecological screening criteria.

The assessment of PFAS concentrations within two trophic levels (i.e. secondary consumers (amphibians) and tertiary consumers (reptiles)) that belong to the semi-terrestrial food web, indicated that bioaccumulation and hence, biomagnification was occurring within the food chain and more specifically, the tertiary consumers sampled as part of the investigation.

CONCEPTUAL SITE MODEL The CSM has been presented in three parts, representing the three primary receiving surface water catchments in the Investigation Area (Louisa Creek/Town Common/Bohle River; Three Mile Creek; Mundy Creek). Summary of the linkages between identified sources, exposure pathways and sensitive receptors for the three catchments is in a graphical representation provided in Figures ES.1, ES.2 and ES.3 overleaf.


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Figure ES.1 Conceptual Site Model for the Three Mile Creek catchment


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Figure ES.2 Conceptual Site Model for the Louisa Creek/Town Common/Bohle River catchment


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Figure ES.3 Conceptual Site Model for the Mundy Creek catchment


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ADOPTED TOXICITY REFERENCE VALUES (TRVs) Toxicity Reference Values (TRVs) for PFAS based on dose (mass of chemical per unit of body weight) were identified for birds, mammals and reptiles based on the results of a literature search and review of other available sources. The TRVs were used in the risk characterisation step to calculate risks for the receptors based on the dose estimates calculated from the food web modelling. TRVs for PFOS and PFOA were adopted as more reliable dietary dose-response studies were available for these particular PFAS compounds. Consideration of other PFAS compounds reported within the various media (such as PFHxS) was also given in the context of their potential toxicity to ecological receptors, there is however relatively limited information available. Therefore, while a TRV for PFHxS has not been adopted in the ERA, it is being evaluated in the Human Health Risk Assessment (HHRA) as an additive with PFOS.

In developing TRVs for ecological receptors, typically a No Observed Adverse Effect Level (NOAEL) and Lowest Observed Adverse Effect Level (LOAEL) can be selected for individual receptor species or receptor groups using several critical toxicity studies. The NOAEL and LOAEL are chronic toxicity (i.e. as a result of long-term exposure to a chemical) values that have been used to determine the concentration of PFAS that the ecosystem can be exposed to without adverse effects or with adverse effects of a certain magnitude. The resulting TRVs are based on the selected NOAEL and LOAEL concentrations.

A summary of the TRVs is provided in Table ES.1.

Table ES.1 Summary of adopted TRVs for birds, reptiles and mammals

SPECIES AND ANALYTE

TRV (mg/kg BW/DAY) TOXICITY ENDPOINT

NOAEL LOAEL

Birds and Reptiles

PFOS 0.077 0.77 Reproductive endpoints (i.e. reduction in fertility, hatchability and offspring survival, and growth of offspring).

PFOA 0.077 0.77 In the absence of TRVs for PFOA, PFOS has been used as a surrogate.

Mammals

PFOS 0.1 0.4 Reproductive endpoints in singular and multi-generational studies, including maternal weight gain, litter size and weight, delayed reflexes and physical development.

PFOA 6.2 7.6 Reproduction and developmental endpoints, including reduction in weight gain, delayed physical development, reduced motor coordination.


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EXPOSURE ASSESSMENT For a receptor to be exposed to a chemical a complete exposure pathway must exist. An exposure pathway describes the path a chemical takes from the source to the receptor. For an exposure pathway to be deemed complete, a source, transport mechanism, point of contact; and an exposure route (i.e. ingestion of plants, soil or biota) at the point of exposure must be present. If all elements are present in a system, the source-pathway-receptor linkage is considered complete and a receptor is potentially at risk. If one of the components is absent, then the source-pathway-receptor linkage is broken. Hence, no risk is considered to be present.

The exposure assessment completed as part of the ERA identified the following incomplete and complete exposure pathways:

INCOMPLETE EXPOSURE PATHWAYS

— Dermal uptake of PFAS from environmental media. Dermal uptake is a minor pathway for PFAS exposure based on our current understanding of the compounds’ ability to cross into and through dermal membranes.

— Direct contact with groundwater within the Investigation Area has not been considered for the ERA as direct sampling of surface water has been undertaken in the various surface water bodies which are connected to the site. It is understood there is potential for groundwater seeps to occur in areas within the Investigation Area (i.e. lower reaches of Mundy Creek). However, this is likely to occur following heavy rain events. A direct assessment of the potential toxicity associated with the consumption/ingestion of surface water PFAS impacts is considered to be a more appropriate approach, as the potential exposure to groundwater is likely to be intermittent.

Of note, the ingestion of PFAS in groundwater was not evaluated as a separate exposure scenario. It has been assumed that surface water samples including samples collected in areas where groundwater is known to discharge to surface waters will provide a better representation of potential exposures as a result of water ingestion.

COMPLETE EXPOSURE PATHWAYS

TERRESTRIAL AND SEMI-TERRESTRIAL ORGANISMS:

Exposure routes considered likely to result in complete pathways for terrestrial and semi-terrestrial organisms are as follows:

— incidental ingestion of PFAS adhered to soil and sediment (i.e. animals – invertebrates and vertebrates) — uptake and bioaccumulation of PFAS from soil moisture (i.e. plants) — ingestion of dissolved PFAS in water sources (i.e. animals drinking from and/or inhabiting water sources) — ingestion of PFAS that has bioaccumulated in food sources (i.e. animals – invertebrates and vertebrates).

Of note, the uptake and bioaccumulation of PFAS from the environment into plants on-Base was assessed based on a comparison to soil data only and was inferred to be complete. Off-Base impacts have been assessed via direct measurement of PFAS in plant samples (samphire, mangrove, seagrass) which indicated an incomplete exposure pathway. This exposure pathway wasn’t included in food web modelling.

AQUATIC ORGANISMS (ESTUARINE AND FRESHWATER):

Exposure routes considered likely to result in complete pathways for aquatic organisms are as follows:

— incidental ingestion of PFAS adhered to sediment (i.e. animals – invertebrates and vertebrates) — uptake and bioaccumulation of PFAS from sediment pore water and/or surface water (all aquatic organisms); and — ingestion of PFAS that has bioaccumulated in food sources (i.e. animals – invertebrate sand vertebrates).

The uptake and bioaccumulation of PFAS into aquatic plants and algae has been assessed via direct measurement of PFAS in plant samples. Theoretical modelling of bioaccumulation into aquatic plants was not considered appropriate given the significant variability in potential exposure concentrations in surface water.


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CONCLUSIONS

LOWER ORDER SPECIES

The potential ecological risk to lower order species (i.e. plants, terrestrial invertebrates, aquatic invertebrates and fish) was assessed via the direct toxicity approach, as these receptors are the most highly exposed to impacts within the environment (i.e. direct contact to PFAS adhered to soil, sediment and/or dissolved in surface water systems). A summary of the potential for impact and for direct toxicity to occur to lower order species as a result of exposure to PFAS in soil, sediment and/or surface water is summarised below in Table ES.2. The potential for direct toxic impact was classified as follows:

— Possible: Average and/or maximum PFOS or PFOA concentrations (for a particular media) exceeded the screening benchmark criteria.

— Unlikely: Average and/or maximum PFOS or PFOA concentrations (for a particular media) were below the screening benchmark criteria.


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Table ES.2 Summary of ecological risks – lower order species

SEASON ANALYTE MEDIA AREA SPECIES GROUP SCREENING ASSESSMENT OUTCOME POTENTIAL FOR DIRECT TOXIC IMPACT

Dry PFOS Soil on-Base Terrestrial/semi-terrestrial plants and invertebrates

Average and/or maximum concentrations were above screening benchmark criteria.

Possible

Surface water Aquatic plants, invertebrates and fish Possible

Sediment Possible

Dry PFOS Soil off-Base Terrestrial/semi-terrestrial plants and invertebrates

Average and maximum concentrations were above screening benchmark criteria.

Possible

Surface water Aquatic plants, invertebrates and fish Average and/or maximum concentrations were above screening benchmark criteria.

Possible

Sediment Average and/or maximum concentrations were above screening benchmark criteria.

Possible

Aquatic biota tissue

Mammals and birds that consume aquatic biota

Above the criteria for birds and/or mammals that consume aquatic biota.

Possible

Wet PFOS Soil on-Base Terrestrial/semi-terrestrial plants and invertebrates

Average was below the screening benchmark criteria but the maximum was above.

NB: only x4 samples collected during the wet season.

Possible. However, small dataset in which to evaluate direct toxic impacts.


Possible

Sediment Possible

Wet PFOS Soil off-base Terrestrial/semi-terrestrial plants and invertebrates

No data to assess direct toxic impacts.


Possible

Sediment Possible


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SEASON ANALYTE MEDIA AREA SPECIES GROUP SCREENING ASSESSMENT OUTCOME POTENTIAL FOR DIRECT TOXIC IMPACT

Dry PFOA Soil on-Base Terrestrial/semi-terrestrial plants and invertebrates

Average and maximum concentrations were below screening benchmark criteria.

Unlikely

Surface water Aquatic plants, invertebrates and fish Average and maximum concentrations were below screening benchmark criteria.

Unlikely

Sediment Unlikely

Dry PFOA Soil off-Base Terrestrial/semi-terrestrial plants and invertebrates


Unlikely

Surface water Aquatic plants, invertebrates and fish Average and maximum concentrations were below screening benchmark criteria.

Unlikely

Sediment Unlikely

Aquatic biota tissue

Mammals and birds that consume aquatic biota

PFOA concentrations were either below the laboratory LOR or below screening benchmark criteria.

Unlikely

Wet PFOA Soil on-Base

Terrestrial/semi-terrestrial plants and invertebrates


Unlikely

Surface water/ sediment

Aquatic plants, invertebrates and fish Average and maximum concentrations were below screening benchmark criteria.

Unlikely

Sediment Unlikely

Wet PFOA Soil off-Base Terrestrial/semi-terrestrial plants and invertebrates

No data to assess direct toxic impacts.

Surface water/ sediment

Aquatic plants, invertebrates and fish Average and maximum concentrations were below screening benchmark criteria.

Unlikely

Sediment Unlikely


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HIGHER ORDER SPECIES

Potential risks to higher order species were evaluated via a combination of direct toxicity impacts for available biota tissue data. Quantitative food web modelling was then undertaken for the selected bird, reptile and mammal species, for both terrestrial/semi-terrestrial and aquatic food webs, to determine a total PFOS intake for each receptor (based on dietary consumption). The modelled intakes were then compared against the relevant TRVs for birds/reptiles and mammals. The following ecological risks to higher order species have been quantitatively predicted via food web modelling and are summarised below in Table ES.3. Of note, potential risks were only quantified for PFOS as concentrations of PFOA across the various media were below the screening benchmark criteria and hence, PFOA was not considered to warrant further quantitative assessment.

The potential risk to higher order species was classified as follows:

— Potential for exposure to bioaccumulated PFOS through the food web: the modelled PFOS intake for a particular trophic level was above the LOAEL and/or the NOAEL.

— Low and acceptable: the modelled PFOS intake for a particular trophic level was below both the LOAEL and the NOAEL.


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Table ES.3 Summary of ecological risks – higher order species

TROPHIC LEVEL DRY SEASON – PREDICTED RISK OUTCOME WET SEASON – PREDICTED RISK OUTCOME

TERRESTRIAL/SEMI-TERRESTRIAL ON-BASE

Herbivorous Mammals Potential for exposure to bioaccumulated PFOS through the food web.

Potential for exposure to bioaccumulated PFOS through the food web.

Invertivorous and Omnivorous Mammals Potential for exposure to bioaccumulated PFOS through the food web.


Herbivorous Birds Potential for exposure to bioaccumulated PFOS through the food web.


Invertivorous and Omnivorous Birds Potential for exposure to bioaccumulated PFOS through the food web.


Predatory Mammals Marginal Marginal

Predatory Reptiles Low and acceptable Low and acceptable

Predatory Birds Potential for exposure to bioaccumulated PFOS through the food web.


TERRESTRIAL/SEMI-TERRESTRIAL OFF-BASE

Herbivorous Mammals Low and acceptable Low and acceptable

Invertivorous and Omnivorous Mammals Low and acceptable Low and acceptable

Herbivorous Birds Low and acceptable Low and acceptable

Invertivorous and Omnivorous Birds Low and acceptable Low and acceptable

Predatory Mammals Low and acceptable Low and acceptable


Predatory Birds Potential for exposure to bioaccumulated PFOS through the food web.



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TROPHIC LEVEL DRY SEASON – PREDICTED RISK OUTCOME WET SEASON – PREDICTED RISK OUTCOME

AQUATIC ON-BASE

Herbivorous Mammals Receptor not evaluated for on-Base as no known aquatic environments supporting herbivorous mammals on-Base.

Invertivorous and Omnivorous Birds Low and acceptable Potential for exposure to bioaccumulated PFOS through the food web.

Predatory Birds Low and acceptable Low and acceptable


Predatory Mammals Marginal Potential for exposure to bioaccumulated PFOS through the food web.

AQUATIC OFF-BASE

Herbivorous Mammals Low and acceptable Low and acceptable

Invertivorous and Omnivorous Birds Low and acceptable Low and acceptable

Predatory Birds Low and acceptable Low and acceptable


Predatory Mammals Low and acceptable Low and acceptable


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In summary, the findings of the ERA have identified that there is a potential for direct toxicity effects to occur to lower order terrestrial/semi-terrestrial and aquatic species (i.e. plants, terrestrial invertebrates, aquatic invertebrates, fish), based on a comparison of the reported soil, surface water, sediment and/or biota tissue concentrations to adopted screening benchmarks.

Further evaluation of potential risks to higher order species was conducted for terrestrial/semi-terrestrial and aquatic receptors via quantitative food web modelling. The results of the quantitative modelling indicated the following:

ON-BASE TERRESTRIAL AND SEMI-TERRESTRIAL RECEPTORS

— Predatory mammals – low and acceptable ecological risk. — Predatory reptiles – low and acceptable ecological risk. — Herbivorous mammals – potential for exposure to bioaccumulated PFOS through the food web. — Invertivorous and omnivorous mammals – potential for exposure to bioaccumulated PFOS through the food web. — Herbivorous birds – potential for exposure to bioaccumulated PFOS through the food web. — Invertivorous and omnivorous birds – potential for exposure to bioaccumulated PFOS through the food web. — Predatory birds – potential for exposure to bioaccumulated PFOS through the food web.

ON-BASE AQUATIC RECEPTORS

— Predatory birds – low and acceptable ecological risk. — Predatory reptiles – low and acceptable ecological risk. — Invertivorous and omnivorous birds – potential for exposure to bioaccumulated PFOS through the food web. — Predatory mammals – potential for exposure to bioaccumulated PFOS through the food web.

OFF-BASE TERRESTRIAL AND SEMI-TERRESTRIAL RECEPTORS

— Herbivorous mammals – low and acceptable ecological risk. — Invertivorous and omnivorous mammals – low and acceptable ecological risk. — Herbivorous birds – low and acceptable ecological risk. — Invertivorous and omnivorous birds – low and acceptable ecological risk. — Predatory mammals – low and acceptable ecological risk. — Predatory reptiles – low and acceptable ecological risk. — Predatory birds – potential for exposure to bioaccumulated PFOS through the food web.

OFF-BASE AQUATIC RECEPTORS

— Herbivorous mammals – low and acceptable ecological risk. — Invertivorous and omnivorous birds – low and acceptable ecological risk. — Predatory birds – low and acceptable ecological risk. — Predatory reptiles – low and acceptable ecological risk. — Predatory mammals – low and acceptable ecological risk.


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ASSUMPTIONS AND LIMITATIONS OF THE ERA This ERA is based on the following key assumptions, limitations and approach to quantifying ecological risks:

— The outcomes of the ERA are based on current concentrations as measured throughout the DSI (WSP 2018a and 2018b) and during aquatic and semi-terrestrial biota sampling events. Therefore, the ERA cannot evaluate potential risks to ecological receptors as a result of changes in PFAS concentrations in the environment since collection of the DSI data and biota samples. Similarly, the ERA has not considered any cumulative impacts to ecological receptors from historical exposure as this is not considered possible (or plausible) as the concentrations within the various media were not known.

— The assessment of potential ecological risks was based on data obtained during the DSI (WSP 2018a and 2018b), during the semi-terrestrial biota sampling event (WSP 2018d) and ESP’s aquatic biota sampling programs between July 2017 and March 2018.

— DSI (WSP 2018a and 2018b) sampling and analysis that targeted both on-Base and off-Base media during the dry and wet season included soil, groundwater, sediment and surface water. Aquatic biota (i.e. finfish, crustaceans, plants and bivalves) samples were collected in the dry season and just prior to the start of the wet season, and semi-terrestrial biota samples were collected just prior to the start of the wet season. Hence, an evaluation for how PFAS concentrations may vary during seasonal changes was not undertaken. Aquatic biota sampling was also limited to seasonal availability of different fish species and accessibility for sampling.

— No site-specific sampling was undertaken for terrestrial invertebrate species (i.e. insects, earthworms etc.). However, earthworm data was utilised from AECOM (2016a) as a substitute.

— The selection of receptors and species in which to sample and/or include within quantitative food web modelling were those which have an affinity with aquatic environments, as it is was assumed that they will have higher exposure to PFAS concentrations present within the environment, and were used to infer or consider potential risks to other trophic levels within only terrestrial environments.

— In the absence of site-specific data for some species/trophic groups including terrestrial invertebrates and herbivorous mammals, the adopted exposure point concentrations were based on available data from other completed Defence investigations, primarily from AECOM (2016a). For terrestrial invertebrates, earthworm data was adopted as a substitute. For herbivorous mammals, rabbit tissue data from AECOM (2016b), was adopted as a substitute.

— In the absence of available wild bird tissue or bird egg data, chicken egg data as reported in AECOM (2016a) was adopted as a representative (substitute) exposure point concentration for quantitative modelling purposes.

— One of the primary uncertainty factors when undertaking food web modelling is the absence of species specific food and water ingestion rates for some Australian species. In the absence of Australian data, it is unclear whether the adopted assumptions would result in an under or over estimation of risks.

— Quantitative food web modelling for higher order species evaluates the potential exposure as a direct result of bioaccumulation of PFAS in the diet of terrestrial/semi-terrestrial and aquatic birds, reptiles and mammals. However, the additional exposure risk associated with biomagnification within higher order species cannot be accounted for or evaluated via food web models.

— The modelling of a receptor’s exposure from ingestion of dietary items assumes all items contain PFAS, however it is more likely that not all dietary components would contain PFAS as they are sourced from different areas and seasonal variation may also occur.

— The whole Investigation Area has been assumed to be contaminated with the concentrations adopted at the point of exposure. This does not account for the range of reported concentrations for various media, as well as seasonal variability which appears to be occurring to some degree. This therefore results in conservative estimates of risks to ecological receptors.


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— The home range value adopted was based on twice the size of the Investigation Area to account for migratory species which move to areas outside the Investigation Area. Given the extensive migration of some bird species (identified in the Investigation Area), the adopted home range value is considered very conservative and therefore likely results in an overestimation of risks to migratory receptors.

— It has been assumed for modelling purposes that the proportion of available suitable habitat within the Investigation Area is 100%. This is considered to be conservative, as it is more likely the migratory species may move outside of the Investigation Area reducing their potential exposure to PFAS. This may result in conservative estimates of risks to these species, but is considered appropriate in the absence of specific data.

— Potential risks for reptiles considered as tertiary consumers (freshwater snake and Canns Longnecked turtle) was quantified using toxicity reference values for avian species as no toxicity or dose-response information is currently available for reptilian species. Little is also known about how they metabolise PFAS or other emerging chemicals. Hence the evaluation of risks to reptilian species via quantitative food web modelling may not be providing a conservative (or representative) risk estimate.

— Domestic animals (both farm and residential) have not been evaluated as part of the ERA as they are not considered to be exposed in the same way as wild ecological receptors (i.e. they are often fed food from other sources including food scraps and/or packaged pet food). They are likely to primarily drink tap water rather than bore water or surface water. Management measures can also be implemented to prevent exposure including the use of reticulated town water instead of groundwater, and supplementing food supply, so that animals are not eating produce grown in impacted soil, groundwater or surface water.

PFAS MANAGEMENT AREA PLAN The data obtained from the investigations to date have been utilised as input to the PFAS Management Area Plan (PMAP) for the Base currently under development. The PMAP seeks to provide management plans to mitigate the potential impact to human health and the environment from identified PFAS in the Investigation Area and to mitigate the potential migration of PFAS off-Base. An ongoing monitoring plan is included within the PMAP to identify changes in PFAS impact over time within the Investigation Area.


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1 INTRODUCTION WSP Australia Pty Ltd (WSP) was commissioned by the Department of Defence (Defence) under the Defence per and poly-fluoroalkyl substances (PFAS) Panel to conduct an Ecological Risk Assessment (ERA) to quantitatively assess the risk to the environment resulting from exposure to the historical use of Aqueous Film Forming Foams (AFFF) containing PFAS at the Royal Australian Air Force (RAAF) Base Townsville. Herein referred to as ‘the Base’, located on Ingham Road, Garbutt, Queensland.

The WSP assessment included the following:

— Review of site history information (and previous assessment reports) to identify potential areas of AFFF use and storage.

— Collection of soil, sediment, surface water, groundwater, aquatic and semi-terrestrial biota samples from areas potentially contaminated by PFAS.

— Comparison of the above sample results to published guidelines (for each media type) for an initial evaluation of potential human health and ecological risk. This information was reported in the Detailed Site Investigation (DSI) Report (WSP, 2018a) and Seasonal Monitoring Report 1 (WSP, 2018b) except for the biota sample results (contained herein) and the Human Health Risk Assessment (HHRA) (WSP, 2018c).

— Where concentrations were reported above the published guideline values, further assessment was required. This document (i.e. the ERA report) documents the evaluation of ecological risk associated with PFAS contamination identified within the Investigation Area for RAAF Base Townsville (refer to Figure 1, Appendix A). An evaluation of human health risk associated with the identified PFAS contamination has been undertaken as part of the HHRA (WSP, 2018c) for the Base.

— This assessment has not addressed potential ecological risks associated with other chemicals.

1.1 BACKGROUND AFFF were stored and used by Defence at the Base for fire-fighting purposes, including routine testing and emergency fire-fighting response practice drills from approximately the 1970s to 2004. AFFF containing PFAS was phased out in approximately 2004 and replaced by another product (Ansulite).

WSP has undertaken a DSI (WSP, 2018a and 2018b) across the Investigation Area (which incorporates both on-Base and off-Base areas), targeting soil, sediment, surface water, groundwater, aquatic and semi-terrestrial biota. A Queensland Department of Environment and Science (DES) accredited auditor, Phil Sinclair of Coffey, was engaged by Defence as the Technical Advisor (TA); and third party reviewer of technical deliverables for the project.

1.2 OBJECTIVES The objectives of the ERA are to:

— assess the potential for PFAS contaminants in soil, sediment, surface water, and groundwater to pose adverse effects to ecological receptors which inhabit within the Investigation Area

— assess the potential for risks to higher order wildlife (i.e. piscivorous birds (birds that eat fish), terrestrial, marine and estuarine mammals; and birds of prey) that eat lower order species containing PFAS; and

— assist in guiding the remediation and/or risk management measures to address PFAS contamination within the Investigation Area.


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2 ERA FRAMEWORK In accordance with the United States Environmental Protection Agency (US EPA), PFAS are classified as emerging contaminants. Thus, information regarding the fate, transport and toxicity of PFAS is the subject of ongoing development with new information becoming available on a regular basis. Hence, the ERA has been prepared in cognisance of this; and in consultation with various stakeholders including the Commonwealth, the Queensland Government, Townsville City Council (TCC), Defence, the TA and Traditional custodians.

The ERA has been undertaken in accordance with the following national guidelines:

— National Environment Protection (Assessment of Site Contamination) Amendment Measure 2013’ (NEPC 2013). The relevant provision within the NEPM is: — Schedule B5 – Guideline on Ecological Risk Assessment.

— Heads of EPAs Australia and New Zealand (HEPA), PFAS National Environmental Management Plan (NEMP), January 2018 (referred to herein as the PFAS NEMP (January 2018).

— Australia and New Zealand Guidance for Fresh and Marine Water Quality. Australian and New Zealand Environment and Conservation Council (ANZECC) and Agriculture and Resource Management Council of Australia and New Zealand (ARMCANZ) (ANZECC 2000).

— Commonwealth Environmental Management Guidance on Perfluorooctane Sulfonic Acid (PFOS) and Perfluorooctanoic Acid (PFOA). Draft dated October 2016 and published December 2016. Department of the Environment and Energy.

Where required, additional guidance has also been sourced from international references and referenced within this ERA report. The selection of potential receptors for each trophic level was based on the findings of the following database searches and primary reference sources:

— Department of the Environment and Energy – http://www.environment.gov.au/cgi-bin/sprat/public/sprat.pl — Australian Museum – https://australianmuseum.net.au/ — Queensland Museum – http://www.qm.qld.gov.au/ — Birdlife Australia – http://birdlife.org.au/ — Birds in Backyards – http://www.birdsinbackyards.net/finder — Australian Reptile Online Database – http://www.arod.com.au/arod/ — International Union for Conservation of Nature (IUCN) Red List – http://www.iucnredlist.org/ — Handbook of the Birds of the World (HBW) Alive – http://www.hbw.com/ — Queensland Department of Science, Information, Technology and Innovation (DSITI) – Wildlife Online — Commonwealth Government’s – Environment Protection and Biodiversity Conservation (EPBC) Act Protected

Matters Search Tool.

The overall approach adopted for the ERA was based on Schedule B5 of the NEPM (NEPC 2013) and is summarised in Figure 2.1.

http://www.environment.gov.au/cgi-bin/sprat/public/sprat.pl

https://australianmuseum.net.au/

http://www.qm.qld.gov.au/

http://birdlife.org.au/

http://www.birdsinbackyards.net/finder

http://www.arod.com.au/arod/

http://www.iucnredlist.org/

http://www.hbw.com/


WSP December 2019

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Figure 2.1 Ecological Risk Assessment framework

Receptor Identification

– Identification of ecological receptors relevant to the assessment

Risk Characterisation

– Characterise the potential for adverse effects to occur on a species or ecosystem scale (depending on data availability) using a weight of evidence approach.

– Evaluate the uncertainty in the data and assumptions adopted

– Summarise risk information

Risk Management

– Define the options and evaluate the environmental health, economic, social and political aspects of the options

– Make informed decisions

– Take actions to implement the decisions

– Monitor and evaluate the effectiveness of the action taken

Toxicity Assessment Collection and analysis of relevant data

– Review qualitative/quantitative toxicity information – Assess Dose-Response relationship – Identify species specific toxicity where possible

– Uncertainty analysis for both hazard identification and dose-response assessment steps

Exposure Assessment

– Identification of exposed populations – Identification of complete and incomplete exposure

pathways

– Estimation of exposure concentration and intakes for

each pathway

Problem Identification

– Review and analysis of relevant site data – Development of a conceptual site model (CSM) to broadly identify ecological

receptors – Selection of environmental screening benchmark criteria that are protective of

identified ecological receptors – Comparison of reported chemical concentrations in environmental media to

adopted screening benchmarks deemed appropriate for use


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2.1 AVAILABLE INFORMATION The ERA has relied on information collected as part of the DSI program (WSP, 2018a and 2018b) as well as data obtained for aquatic biota sampling by Ecological Service Professionals Pty Ltd (ESP).

The information and data that has formed the basis of the ERA includes the following reports which document the collection and analysis of environmental media inclusive of biota, as used in this risk assessment:

— AECOM (2015) Town Common Rehabilitation and Maintenance Management, Mt St John WWTP. — ESP (2018a), RAAF Base Townsville – PFAS Investigation Aquatic Biota Sampling and Analysis, July 2018.

Prepared by Ecological Service Professionals Pty Ltd. — ESP (2018b), RAAF Base Townsville – PFAS Investigation Estuarine Biota Sampling and Analysis, July 2018.

Prepared by Ecological Service Professionals Pty Ltd. — ESP (2018c), RAAF Base Townsville – PFAS Investigation Marine Biota Sampling and Analysis, August 2018.

Prepared by Ecological Service Professionals Pty Ltd. — WSP (2018a), RAAF Base Townsville Detailed Site Investigation. WSP Australia Pty Ltd.

— PFAS Volume 1: Main Report, 02 May 2018. — PFAS Volume 2: Appendices A & B, 02 May April 2018. — PFAS Volume 3: Appendices C to I, 02 May 2018.

— WSP (2018b), RAAF Townsville Seasonal Monitoring Report 1 – PFAS. WSP Australia Pty Ltd. — PFAS Volume 1: Main Report, 18 December 2018. — PFAS Volume 2: Appendices A & B, 18 December 2018. — PFAS Volume 3: Appendices C & D, 18 December 2018. — PFAS Volume 4: Appendices E, 18 December 2018.

— WSP (2018d), RAAF Base Townsville – PFAS Investigation Semi-Terrestrial Biota Sampling and Analysis, June 2018. WSP Australia Pty Ltd.

Wet season data is presented in the Seasonal Monitoring Report 1 (WSP 2018b) and the wet season data for groundwater, surface water and sediments has also been incorporated into this ERA report, with tabulated result tables presented in Appendix B. Potential risks to ecological receptors were quantitatively assessed using the wet season groundwater, surface water and sediment results. No additional aquatic biota samples were collected during the wet season.

2.2 KEY ASSUMPTIONS AND LIMITATIONS OF THE ERA This ERA is based on the following key assumptions and limitations:

— The outcomes of the ERA are based on current concentrations as measured throughout the DSI (WSP, 2018a and 2018b) and during aquatic and semi-terrestrial biota sampling events. Therefore, the ERA cannot evaluate potential risks to ecological receptors as a result of changes in PFAS concentrations in the environment since collection of the DSI data and biota samples. Similarly, the ERA has not considered any cumulative impacts to ecological receptors from historical exposure as this is not considered possible (or plausible) as the concentrations within the various media were not known.

— The assessment of potential ecological risks was based on data obtained during the DSI (WSP, 2018a and 2018b), during the semi-terrestrial biota sampling event (WSP, 2018d) and ESP’s aquatic biota sampling programs between July 2017 and March 2018.

— DSI (WSP, 2018a and 2018b) sampling and analysis that targeted both on-Base and off-Base media during the dry and wet season included soil, groundwater, sediment and surface water. Aquatic biota (i.e. finfish, crustaceans, plants and bivalves) samples were collected in the dry season and just prior to the start of the wet season, and semi-terrestrial biota samples were collected just prior to the start of the wet season. Hence, an evaluation for how PFAS concentrations may vary during seasonal changes was not undertaken. Aquatic biota sampling was also limited to seasonal availability of different fish species and accessibility for sampling.


WSP December 2019

Page 5

— No site-specific sampling was undertaken for terrestrial invertebrate species (i.e. insects, earthworms etc.). However, earthworm data was utilised from AECOM (2016) as a substitute.

— The selection of receptors and species in which to sample and/or include within quantitative food web modelling were those which have an affinity with aquatic environments, as it is was assumed that they will have higher exposure to PFAS concentrations present within the environment, and were used to infer or consider potential risks to other trophic levels within only terrestrial environments.

— In the absence of site-specific data for some species/trophic groups including terrestrial vertebrates and herbivorous mammals, the adopted exposure point concentrations were based on available data from other completed Defence investigations, primarily from AECOM (2016). For terrestrial invertebrates, earthworm data was adopted as a substitute. For herbivorous mammals, rabbit tissue data from AECOM (2018), was adopted as a substitute.

— In the absence of available wild bird tissue or bird egg data, chicken egg data as reported in AECOM (2016) was adopted as a representative (substitute) exposure point concentration for quantitative modelling purposes.

— One of the primary uncertainty factors when undertaking food web modelling is the absence of species specific food and water ingestion rates for some Australian species. In the absence of Australian data, it is unclear whether the adopted assumptions would result in an under or over estimation of risks.

— Quantitative food web modelling for higher order species evaluates the potential exposure as a direct result of bioaccumulation of PFAS in the diet of terrestrial/semi-terrestrial and aquatic birds, reptiles and mammals. However, the additional exposure risk associated with biomagnification within higher order species cannot be accounted for or evaluated via food web models.

— The modelling of a receptor’s exposure from ingestion of dietary items assumes all items contain PFAS, however it is more likely that not all dietary components would contain PFAS as they are sourced from different areas and seasonal variation may also occur.

— The whole Investigation Area has been assumed to be contaminated with the concentrations adopted at the point of exposure. This does not account for the range of reported concentrations for various media, as well as seasonal variability which appears to be occurring to some degree. This therefore likely results in conservative estimates of risks to ecological receptors.

— The home range value adopted was based on twice the size of the Investigation Area to account for migratory species which move to areas outside the Investigation Area. Given the extensive migration of some bird species (identified in the Investigation Area), the adopted home range value is considered very conservative and therefore likely results in an overestimation of risks to migratory receptors.

— It has been assumed for modelling purposes that the proportion of available suitable habitat within the Investigation Area is 100%. This is considered to be conservative, as it is more likely the migratory species may move outside of the Investigation Area reducing their potential exposure to PFAS. This may result in conservative estimates of risks to these species, but is considered appropriate in the absence of specific data.

— Potential risks for reptiles considered as tertiary consumers (freshwater snake and Canns Longnecked turtle) was quantified using toxicity reference values for avian species as no toxicity or dose-response information is currently available for reptilian species. Little is also known about how they metabolise PFAS or other emerging chemicals. Hence the evaluation of risks to reptilian species via quantitative food web modelling may not be providing a conservative (or representative) risk estimate.

— Domestic animals (both farm and residential) have not been evaluated as part of the ERA as they are not considered to be exposed in the same way as wild ecological receptors (i.e. they are often fed food from other sources including food scraps and/or packaged pet food). They are likely to primarily drink tap water rather than bore water or surface water. Management measures can also be implemented to prevent exposure including the use of reticulated town water instead of groundwater, and supplementing food supply, so that animals are not eating produce grown in impacted soil, groundwater or surface water.

Documents

VOLUME 1: Executive Summary · 2019-12-04 · Project No PS102571 RAAF Base Townsville - Ecological Risk Assessment (ERA) Volume 1: Main Report Department of Defence WSP December